Layout error with struct that includes __attribute__((aligned(8)))

I encountered this error when trying to generate bindings for Fio.

Input C/C++ Header

typedef long a;
typedef b;
typedef a c;
typedef struct {
  union {
    c d
  };
} e;
struct thread_stat {
  b f;
  e g;
  c h __attribute__((aligned(8)))
} __attribute__((packed));

Bindgen Invocation

bindgen --whitelist-type=thread_stat isolated-test-case.h

Actual Results

---- ffi::bindgen_test_layout_thread_stat stdout ----
thread 'ffi::bindgen_test_layout_thread_stat' panicked at 'assertion failed: `(left == right)`
  left: `8`,
 right: `4`: Offset of field: thread_stat::g', src/ffi.rs:81:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    ffi::bindgen_test_layout_thread_stat

and/or

Expected Results

No errors from the layout tests

Reproduce the issue with the header in isolated-test-case.h and the shown bindgen invocation, then inspect the generated layout test and the assertion in src/ffi.rs. The work is done when the thread_stat layout test passes without offset errors for the aligned field.